Tuesday, July 22, 2008

Sea tulips, seagrass, worm, and hydroids

By now, I am getting picky in photographing sea tulips. But I still did these ones because they looked different.

These sea tulips look very much like the one shown in Australian Marine Life (Graham J Edgar's book). So I would think they are Pyura australis. But these didn't have stalks! In fact they were fused into one together with the wireweed (Amphibolis species). Anyway, the arrow - that's where something just popped out that made me jump!

WORMS! They never fail to give me the creeps. Marine or not.
And I was so happy that I have stuck to Chai's Rule for Beachcombing No. 1 : Never touch anything with your bare hands. At all.

And I don't like the way they wiggle :(

But well, this small of clump of sea tulips and seagrass is home to some hydroids too. How amazing that you can find several taxonomic groups co-existing in a clump.

I wasn't so sure about it initially. But after looking up a few books, I think the red arrow points to a bunch of hydroids. The black one points to some seaweed or algae. Hydroids are animals. In fact the feather-like structure is a colony of many tiny polyps. As typical of cnidarians, these guys sting. Their more famous hydrozoan relatives that are also colonies (not single animals) - the blue bottle (Physalis physalis) and By the wind sailor (Velella velella).

Another shot of them. Both were attached to the stalk of a wireweed - again! What a wonderful seagrass it is, providing a surface to live on for other animals and plants.

The first 4 photos were taken at South Beach, Freo; the last two, South Cottesloe beach.


Mosura said...

It's like a whole mini ecosystem of it's own :-)

Tsun-Thai Chai said...

Hi Alan,

Yeah! I find that really interesting.
You know what - one reason why I enjoy beachcombing and snorkeling so much is that I like the excitement I get whenever I bump into something new - it is like re-living childhood!

Another reason is that I am trying to have a functional life outside my PhD :(

Brian said...

hey buddy did you take a closer look? Bryozoans can have a similar colonial structure to hydrozoans. one of the ways to tell is bryozoans will have hollow, cillated tentacles, hydrozoans have uncilliated solid tentacles. both groups have zooid differentiation. (ps u will need to take a sample under a microscope to see the difference)
im intrested to know what it really is! tell us!

Tsun-Thai Chai said...

Hi Brian,

Thanks for the tip. I don't think I can get them home and put them under a microscope. You are just not meant to take anything from that beach - marine park rules :)

But thanks. Will keep that in mind.